Re: [Vala] [gnome-db] DataBase as a Gee Collection of Collections

[Daniel Espinosa <esodan gmail com>]

2011/12/23 Vivien Malerba <vmalerba gmail com>:
> On 22 December 2011 22:01, Daniel Espinosa <esodan gmail com> wrote:
> > I'm planning to create an implementation of interfaces to access a
> > database with classes and interfaces from Gee.
> >
> > This thread is planned to collect comments, suggestions and track
> > implementations. May be I can add a link on live.gnome.org when I have
> > something functional and solid plans.
> >
> > First Concepts:
> >
> > * A database is a collection of schemas and other objects
> > * Each schema have a collection of tables, views and other objects
> > that have Rows
> > * A Row is a collection of values with different types and with
> > attributes like: PRIMARY KEY, NAME, TYPE, VALUE, REFERENCEDBY,
> > REFERENCE
> > * REFERENCEBY and REFERENCE attributes can be used to get a collection
> > of related values from other table collection
> >
> >
> > First implementation ideas:
> >
> > * Define Interfaces and implementator classes , like Gee does, to
> > allow any one to access any kind of data. For now current GDA's
> > infrastructure will be used.
>
>
> Libgda reports all this information in a GdaMetaStruct object.
>
> Regards,
>
> Vivien

I've commited first interfaces as general concept. They uses Vala
Generics in order to help any other to implement them whitout a fixed
implementation. Added interfaces[1] include DbCollection (Database
abstraction as a collection of collections), DbSchema, DbTable,
DbRecord and DbField.

Derived class will use GdaMetaStruct on demand to retrieve database
information and expose as expected by the interfaces.

May be I'll propose a new Gee interface called Selectable, where
implementors must define a 'select (SqlWhere)' method with SqlWhere as
a tree of SqlExpressions to define simple to complex conditions. These
could be the first steps to add LinQ support to Vala.

On GDA implementations I plan to use GdaSqlBuilder and SqlStatements
to implement Selectable interface and include as a pre-
requisite for DbTable interface.

[1] http://git.gnome.org/browse/libgda/commit/?id=04317b0316398dbe29ad24043219efe735ff1af7

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